This invention relates to miniaturized devices for the controlled exposure or release of molecules such as drugs and/or secondary devices such as sensors.
U.S. Pat. No. 5,797,898 to Santini Jr., et al. discloses microchip delivery devices which have a plurality, typically hundreds to thousands, of tiny reservoirs in which each reservoir has a reservoir cap positioned on the reservoir over the molecules, so that the chemical molecules (e.g., drugs) are released from the device by diffusion through or upon disintegration of the reservoir caps. The reservoirs may have caps made of a material that degrades at a known rate or that has a known permeability (passive release), or the caps may include a conductive material capable of dissolving or becoming permeable upon application of an electrical potential (active release).
In the active release devices, the reservoir cap can be a thin metal film. Application of an electric potential causes the metal film to oxidize and disintegrate, exposing the contents of the reservoir to the environment at the site of the microchip device. It would be advantageous to enhance this oxidation and disintegration across the surface of the metal film, in order to achieve consistent and reliable exposure of the molecules and secondary devices contained in the reservoirs. It would be particularly desirable, for example, to provide microchip devices that provide highly reliable and precise exposure of drug molecules located in reservoirs in the microchip delivery devices to the environment in which the microchip device is implanted. More generally, it would be desirable to provide devices and methods to enhance the opening of reservoir caps in microchip devices for the controlled exposure or release of reservoir contents.